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Date: Wed, 9 Sep 2015 14:30:27 +0100
From: David Vrabel <david.vrabel@citrix.com>
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To: Josh Poimboeuf <jpoimboe@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
        <x86@kernel.org>
CC: <linux-kernel@vger.kernel.org>, <live-patching@vger.kernel.org>,
        "Michal Marek" <mmarek@suse.cz>, Peter Zijlstra <peterz@infradead.org>,
        "Andy Lutomirski" <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andi Kleen <andi@firstfloor.org>, "Pedro Alves" <palves@redhat.com>,
        Namhyung Kim <namhyung@gmail.com>,
        "Bernd Petrovitsch" <bernd@petrovitsch.priv.at>,
        Chris J Arges <chris.j.arges@canonical.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH v12 07/21] x86/xen: Add stack frame dependency to hypercall
 inline asm calls
References: <cover.1441749989.git.jpoimboe@redhat.com>
 <ec811627e3a3e3ff138cf7e47e89ce43cbaf30ef.1441749989.git.jpoimboe@redhat.com>
In-Reply-To: <ec811627e3a3e3ff138cf7e47e89ce43cbaf30ef.1441749989.git.jpoimboe@redhat.com>
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On 09/09/15 14:21, Josh Poimboeuf wrote:
> If a hypercall is inlined at the beginning of a function, gcc can insert
> the call instruction before setting up a stack frame, which breaks frame
> pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
> a bad stack trace.
> 
> Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by
> listing the stack pointer as an output operand for the hypercall inline
> asm statements.

Reviewed-by: David Vrabel <david.vrabel@citrix.com>

David